Wattmeteb



w. M. BRADSHAW 117A. w. COPLEY...

WMTMETER. APPLICATIONP11121) MAR.9.1912.

1916. 2 SHEETS-SHEET l. n

Patented Aug. 8

@l VENTOR *awww friction.

UNITED STATES PATENT, oFFioE.

WILLIAM M. BRADSHAW AND ALMON W. COPLEY, 0F WILKINSBURG, PENNSYLVANIA,

i ASSIGNORS TO WESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A COIEIf PORATION OF PENNSYLVANIA.

To all whom t may concern:

Be it known that we, WILLIAM M. BRAD- sHAw and ALMON W. COPLEY, citizens of the United States, and residents of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have 1invented a new and useful Improvement in Watt'meters, of which the following is a specification.

Our invention relates to wattmeters and similar motormeters for use in connection with alternating current circuits, and it has for one of its objects to provide a wattmeter having an exceptionally high degree of accuracy in operation over a wide range of fluctuatlons 'of voltage, load, power factor and frequency, and.y which 1s also exceedingly simple, compact and. light in construe-r tion.

provide highly ,effective and convenient means for adjusting the compensation for Our invention isillustrated in the accompanying drawings, Figure 1 of which is a front face view of'a wattmeter that is ofthe cover and-certain other parts thereof being broken away for the sake of clearness of illustration. Fig. 2 is a View, partially in side elevation and partially in section, df the meter of-Fig. 1. Fig. 3 is a face View of the principal operating parts of the meter with the circuit connections thereof shown diagrammatically. Fig. 4 is a plan and sectional view of the core or magnetic circuit of the meter along the line Ivi-IV of Fig. 3, and Fig. 5 is a partial plan view of the armature and magnetic circuit showing their relations to eachother. p

kThe operating partsl of the meter are mounted within a base orbox 1 for which a removable cover 2 is provided, the said opyeratmg parts comprising a vlaminated electromagnet or core member 3, that is Secured to bosses or seats 4 upon the bottom inner face of the base by means of tap bolts 5, which also serve to secure an iron cover 6 in position over the outer face of theelectromagnet yfor shielding the same from external magnetism. The main portion of the electromagnet 3- is o f substantially the form specification of Letters Patent.

A further object of our inventionis to WATTMETER.

Patented Aug. s, 1916.

Application sie@ March 9, 1912. serial No. 682,797.

'is provided with air gaps to form poles that are disposed adjacent to a rotatable conducting disk 9 constituting the armature or movable. element of the meter. Thecorner portions of the extended pole `,faces are located substantially opposite tothe edge of the armature, as shown lin Fig.. 5.

An arm-11, that is integral with the base and extends forwardly therefrom, is provided with a plane surface directly opposite the poles. of the electromagnet, the 'disk 9 being interposed between the said surface and the electromagnet'. Ihe extension of the central leg 7 of the magnet is provided with a partially inclosed slot 8a near its polar extremity, the outer end of the slot'being preferably only of suflicient width toN permit of the insertion of the wires of coils `to be hereinafter described. The outer legs 7"L are provided with lateral extensions 13 which constitute pole shoes and serve to enlarge the polar area of the magnet.

The central leg ofl the electromagnet is provided with a potential winding 14 that4 is adapted to be connected in shunt to, or

between the conductors of, the circuit 15-16 in connection with which the instrument is employed for the purpose of measuring the energy traversing it. The polar extremities of the legs of the eleetromagnet are provided With two series or load coils 17'that occupy a slot 8a in the end of the central leg fand the spaces behind the pole shoes 13 on the other legs, and respectively surround parts of the middle leg and the outer legs -and also span the air gaps between them,

the said coils being connected in series with one of the conductors 16 of the circuit l5- 16,01' being otherwise supplied with current that is proportional to the current traversing the said circuit.

The movemcntS of .the rotatable disk 9 are `sis retarded by means of a permanent magnet 18 that is carried by a post 19 which is formed integral with, and extends forward from, the base. The polar extremities ofthe magnets are disposed adjacent to the disk and are opposite an armature 20 that is located upon the other side of the disk and is carried by the arm 11. The armature 20 is mounted upon a stud 21 that is screwed into the arm 11, so that its distance from the permanent 'magnet and the disk may be adjusted for the purpose of regulating the degree of damping afforded by the permanent ma et, a--set screw 22 being rovided forsecuring the armature in its a ]usted' position.

Adjustable means are also provided for compensating for friction or light load, the said means comprising two formed sheet metal closed-cireiiit conductors 23 that are pivotally mounted upon bolts 24 which extend through holes in the electroinagnet core and assist in securing the laminas together. The inner ends of the conductors 23 are located and moyable in the curved air gaps 8 between the central and outer legs of the electromagnet. The closedcircuit conductors 23 are connected together for simultaneous rotative movement by means of a bar 25 having slots through which the bolts 24 project, auxiliary nuts or studs 26 and 27 that project through the cover 6, being screwed upon the front ends of the said bolts. The bar 25 carries two pins 28 that project into apertures in lugs 29 that are formed integral with the closed-circuit conductors. `One en d of the bar 25 is bentforward substantially parallel to the nut 26 and is provided with an aperture to receive i; screw 30 that is screwed into the side of the nut 26 and is surrounded by a helical compression spring 31 for forcing the laterally bent end of the bar against the head of the screw. Thus, by turning the screw 30, the positions of the ends or portions of the closed-circuit conductors that are located in the air gaps of the electromagnet are varied, the said ends of the closed-circuit conductors being moved in opposite directions. The outer face of the laterally bent end of the bar 25 is provided with an arrow and with letters S and F to indicate the directions of rotation of the screw 30 for causing the meter to run either slow or fast. against lost-motion between the closed-'circuit coiiductors 23 and the pins 28, helical springs 32 surround the supporting bolts 24 andihave extensions that respectively engage the ends of the closed-circiiit conductors and the core member 7n. (See Fi s.` 3 and 4). The nut or stud 27 serves to loc t the parts in any position to which they may be adjusted.

In order that the meter may be accurate with changes in the power factor of the cir- (See Fig. 2)* To insure` cuit in connection with which it is employed, the polar end of the middle leg of the electromagnet is surrounded by a closed-circuit conductor or coil 33 that is adjustable vertically or lon itudinally of said leg, or the resistance of wiich, is variable in any suitable manner.

The peculiarities of construction of the present meter which we regard as important, are the placing of the potential winding and the total load windings upon the saine mag- 1 netizable core or magnet and upon one side only of the rotatable disk, with the load coils surrounding polar extensions of, and the air gaps between, `the legs of the magnet. By this arrangement, a high degree of alternating polarization is secured which renders the meter exceedingly sensitive to changes of current in the load coils and consequently Very accurate, even upon very light loads.

The lateral extensions or shoes upon the the load is-increasedand substantial accu-` racy of the meter registrations is maintained throughout the entire range of operation.

The amounts of-both iron and copper in the present device are also very small as a result ofthe peculiarities of construction above set forth. The meter is consequently light,

compact and inexpensive. Furthermore, adl jiistments for friction or light load may be readily and conveniently effected by the proper rotation of a single screw for which directions are given adjacent to the screw so that no confusion will be likely to occur.

We are aware that it is old to provide a meter with a magnctizable core comprising a middle leg surrounded by the potential coil land outer legs that are'separated at one end from the middle leg by small air gaps with a part of the series winding surrounding the separated ends ofthe core legs, but in all such meters with which we are familiar an additional part of the series winding is provided upon the opposite side of the rotatable disk. Furthermore, the polar faces of the cores of such prior structures have not been enlarged by the p`rovision of lateral extensions or shoes u on iisl the poles, resulting in different flux distribu?l tions from thatf'obtainfed by the present A A l structure. We, of course, make no claim t0l such prior structures, but have carefully distinguished our invention from them.

While the present device is particularly adapted to the measurement of energy` it is primarily a motor, and we accordingly intend that the appended claims should be construed to include allA motors coming within their terms, irrespective of the purposes for which they are employed.

Although the specific form of construction shown has been found highly effective and is that which is preferred, it is obvious that many modifications may be made thereof within the spirit of the invention, and

we desire to include all such modication's within the scope of the appended claims.

We claim as our invention: l. An alternating current motor meter comprising a rotatable disk, a magnetizable core having polar members that are separated by a small air gap, certain of said polar members being provided witha laterally extending horn to permit proximate relationship between the polar surface of the core and-the edge ofthe disk, whereby the torque of the meter is increased and substantial accuracy ofits registrations is maintained, a potential coil upon the core, and a series winding surrounding the separated portions of the polar members behind the horn and constituting the total series winding of the meter. l p

2. An alternating current motor meter comprising an armature, a magnetizable core having polar members that are sep-.1 rated by small air'g'aps and are disposed adjacent to one side only of the armature, cerv tain of said polar members being provided with laterally extending horns, whereby corner portions of the poles are brought substantially opposite to the edge of the armature, a potential coil upon the core, and a series winding surrounding the separated portions of the polar members behind the horns and constituting the total series winding of the meter.

3. An alternating current motor-meter comprising a rotatable disk, a magnetizable core having a central member and side members joined to one end of the central mem.- ber and separated from its other end by small air gaps, the central member being provided with a slot in its free end and the free ends of the side members being provided fwith lateral extensions to permit proximate relationship between the polar surface of the core and the edge of thev disk, whereby the'torque of the meter is increased and sub* stantial accuracy of its Vregistrations is maintained, a complete series winding partially located in the slot in the central member and surrounding the adj acent ends of the side members, and a potential coil upon the core..

4. An alternating current motor-meter 'comprising a magnetizable core having a central member and side members Joined to one end of theV central member andseparated from its other end by small air gaps,

the central member beingprovided near its ree end with a slot that is partially closed and the free ends of the, si'de members being provided with lateral polar extensions that project outwardly, a series winding partially located in the slot in the central member and surrounding the adjacent free ends of the sidemembers, the said winding constituting the total series winding of the meter, and a potential coilupon the core.

5. In an alternating current motor-meter, the combination with a magnetizable core having a central member and side members separated therefrom at one end by air gaps, of two closed-circuit conductors having sides movable respectively in said air gaps, yand means for simultaneously but oppositely adj usting the positions of the said sides of the y conductors in the air gaps.

6. In an alternating current motor-meter, the combination with a magnetizable core having a central member andy side members separated therefrom at one end by air gaps, of two closed-circuit conductors having sides movable respectively in said air gaps, and means for simultaneously adjusting the positions of the said sides of the conductors in the air gaps.

7. An alternating current motor-meter 8. An alternating current motor-meter comprising a. rotatable disk, a magnetizable vcore having polar members that are sepav rated bysmall air gaps, certain oi said polar vmembers being provided with laterally ex.` 'tending horns disposed in proximity to the edge of the disk, a potential coil upon the core, and a series winding` surrounding the separated portions of the core members behind the horns and constituting the total series winding of the meter.

9. ln au alternating current motor-nleter. the'coinbiuation with a rotatable disk, and a magnetizable core eomlirising polar inclu bers that are separated by Small air gaps iio.

.g 4 momma a 'plurality of-laterally extending horns subscribed ourname` this 24th day of Febvlhereby the fxortions of the core adjacent to mary, 1912.

.t e edg'e of t o disk a im close roxmt I thereto, of a potential ilfupon th) core an lv O-,QSIIAW 5 as'eres Winding surrounding the separated A portions of the polarmembers and consti- Witnesses; h tuting the total sores winding of the met-er. B. B. HINES,

In testimony whereof, we have hereunto PAUL MACGAHAN. 

